1. Field of the Invention
This invention relates to an infrared-ray absorption film that will be suitable for an infrared-ray sensor having improved detection sensitivity.
2. Description of the Related Art
A heat-type infrared-ray sensor for detecting infrared-rays by utilizing the change of an electric resistance value depending on a temperature change has been utilized in the past and its infrared-ray detection portion has an infrared-ray absorption film. Gold black is used in many cases as the infrared-ray absorption film because it exhibits high absorption efficiency to the infrared-rays (refer to Japanese Unexamined Patent Publication (Kokai) No. 2003-65481, for example). However, because a vacuum process such as vacuum deposition has been used ordinarily for forming the film, the gold black film is not free from the problem of high cost.